Synonyms/Common Names/Related Substances:

• ALA, alpha-linolenic acid (ALA, C18:3n-3), cod liver oil, coldwater fish, DHA, docosahexaenoic acid (DHA, C22:6n-3), docosapentaenoic acid (DPA, 22:5n-3), DPA, eicosapentaenoic acid (EPA, C20:5n-3), EPA, fish body oil, fish extract, fish liver oil, fish oil fatty acids, halibut oil, long-chain polyunsaturated fatty acids, Lovaza®, mackerel oil, marine oil, MaxEPA®, menhaden oil, n-3 fatty acids, n-3 polyunsaturated fatty acids, Omacor®, Omegaven®, omega fatty acids, omega-3 fatty acids, omega-3 oils, polyunsaturated fatty acids (PUFA), salmon oil, seal oil, shark liver oil, w-3 fatty acids.
• Note: This professional monograph is based on a search of omega-3 fatty acids, and not the individual omega-3 fatty acids. Additional professional monographs are available on DHA, EPA, fish oil, and alpha-linolenic acid (ALA). Omega-3 fatty acids should not be confused with omega-6 fatty acids.

Clinical Bottom Line/Effectiveness

Brief Background:

• Ingestion of cod liver oil became popular in 19th Century England as a source of vitamin D for sun-deprived children. More recently, interest in fish oil as a cardiovascular protectant has stemmed from observations that Greenland Inuit people enjoy an unusually low incidence of heart disease despite a diet high in fat. It has been recognized that their diet is rich in omega-3 fatty acids and relatively lower in omega-6 fatty acids and saturated fatty acids compared to other populations.
• The primary essential fatty acids in the human diet are omega-3 and omega-6 fatty acids. Dietary sources of omega-3 fatty acids include fish oil and certain plant and nut oils. Omega-6 fatty acids are primarily provided in the diet by palm, soybean, rapeseed, and sunflower oils. Omega-9 fatty acids are not considered essential, because they can be produced within the body. Sources of omega-9 fatty acids include animal fat and olive oil. Fish oil contains the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA); some nuts (English walnuts), seeds (flaxseed), and vegetable oils (canola, soybean, flaxseed/linseed, olive) contain alpha-linolenic acid (ALA), which can be converted to EPA and DHA in the body.
• The optimal ratio of omega-6 to omega-3 fatty acids is 4:1, while the American diet generally provides a ratio of 20-30:1 (1). In the United States, the percentages of DHA and EPA have been found to be lower than in other nations with lower cardiac disease incidence, such as Japan (2). An increased proportion of omega-6 fatty acids has been linked to a proinflammatory and prothrombotic state, which increases the risk of a variety of health conditions, including cardiovascular disease and depression.
• Omega-3 fatty acids have long been known to play critical roles in growth but have more recently suggested as providing a wide range of health benefits, several of which are well supported in the literature, including reductions in the risk of coronary heart disease and regulating cholesterol. Studies investigating treatment of other conditions, such as cancer and certain psychological or neurological disorders (depression and attention-deficit hyperactivity disorder (ADHD)), have also shown promising early results. Due to these and other purported health benefits, fish oil, naturally rich in omega-3 fatty acids, has gained popularity as a dietary supplement.
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Dosing/Toxicology

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Precautions/Contraindications

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Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

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Mechanism of Action

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History

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Evidence Table

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Evidence Discussion

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Products Studied

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Author Information

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References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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